More and more modern applications require the use of antennas. The applications include wireless communication devices such as mobile phones and other portable devices sending and/or receiving wireless signals. Recently, RFID integrated circuit tags were developed, and are gaining popularity. A common feature of these devices is portability, which demands these devices to be small. Therefore, integrated antennas are formed in the same semiconductor chips as other integrated circuits are developed.
FIG. 1 illustrates a top view of a conventional integrated circuit structure, which includes antenna 4 formed in semiconductor chip 2. The conventional antenna 4, however, suffers from drawbacks. First, partially due to the large area antenna 4 requires, and the spacing required for separating antenna 4 from other integrated circuits in semiconductor chip 2, antenna 4 requires a large chip area. In addition, seal ring 6 is close to the edges of semiconductor chip 2, and hence encircles antenna 4. Seal ring 6 has the side effect of reflecting and isolating the signal received/sent by antenna 4. Accordingly, antenna 4 can only effectively receive or send signals in the direction vertical to the surface of semiconductor chip 2. This significantly reduces the efficiency of antenna 4. As compensation, antenna 4 may need to be enlarged in order to achieve the required signal strength.
Accordingly, what is needed in the art is a new antenna structure with greater efficiency, and occupying a smaller chip area.